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United States Patent RAILROAD ROLLING STOCK CLEANERS Arthur Frank Butcosk, Fairfax County, Va.

No Drawing. Application January 10, 1957 Serial No. 633,394

4 Claims. (Cl. 252-436) This invention relates to cleaning compounds for use on exterior surfaces of railroad locomotives and pas senger cars and other similar rolling stock, the present application being a continuation-in-part of my prior application Serial No. 376,251, filed August 24, 1953, now abandoned.

Modern railroad rolling stock is constructed with a protective and decorative exterior sheathing laid over the strength members or frame of the car or locomotive. In many cases, this sheathing may consist of metal panels which are provided along their adjoining edges with locking beads that are adapted to form a tight seam between adjacent panels and which assist in holding the panels in position on the vehicle body. Although the seams formed between the locking beads may originally be sealed, the sealing is eventually destroyed in the course of normal use of the vehicle, and the outer sheathing of the vehicle is then no longer fluid tight. Cleaning solutions used on such vehicles are then able to pass through the open seams and collect in pools in the space formed between the sheathing and the internal wall of the vehicle, in which space the strength members are located. Cleaning solutions heretofore used cause serious cor rosion of the strength members especially at the interface of the atmosphere and the surface of the aqueous cleaning solution. The corrosion thus caused is so severe that sections of the strength members so affected must be periodically replaced. This is obviously a costly consequence since in addition to the cost of the materials and labor required to effect the repairs, losses also accrue from retiring the vehicle from service for the time necessary to make the repairs.

In many cases the type of soiling encountered in railroad passenger cars is highly alkaline due to encrustations of calcium carbonate picked up from the roadbed, and a cleaner having a high acidity is necessary to obtain an etficient washing and rinsing action. The purpose of this invention is to provide a special cleaning composition which in an aqueous solution is relatively acidic and which has been modified so as to prevent the acidic nature of the compound from causing atmospheric corrosion of the metal members with which the cleaning solution comes into contact. It has been found that the necessary acidity (a pH of about 1) can be imparted to a cleaning composition by employing sodium acid sulfate as a filling agent, along with the necessary wetting, sequestering, corrosion preventing and dispersing agents, providing that certain relatively small proportions of benzaldehyde are employed to prevent atmospheric corrosion which would otherwise occur. It has been found that benzaldehyde, when employed as indicated more specifically in the following examples, enhances the cleaning action of a solution in addition to preventing atmospheric corrosion.

FER EIt-E EXAIIE: ER

r Ice 1 2,901,434

Patented Aug. 25, 1959 The essential components and proportions of a formulation according to this invention include a softener such as sodium hexametaphosphate and/or sodium tripolyphosphate, and/ or sodium pyrophosphate in amounts of .15 to 5%, a cellulose dispersing agent such as sodium carboxymethyl cellulose in amounts of .10 to 3%, a soluble magnesium compound in amounts of .25 to 10%, a compound comprising a strongly acid reacting radical such as sodium acid sulfate in amounts of to and a wetting agent, or combination of wetting agents in an amount of about 3 to 6%, all percentages being by weight of the total weight of the formulation. Suitable wetting agents which may be used alone or in combination include those such as the alkyl aryl polyether alcohols (Glim, the trade name of B. T. Babbitt, Inc., for its non-ionic polyoxyethylene derivative of alkyl phenol, or Triton X-100, the trade name of Rohm and Haas for p-iso-octylphenyl ether of polyethylene glycol containing 70.3% by weight combined ethylene oxide, having an HLP of 13 and 10-12 mols ethylene oxide), sodium sulfonated alcohol, particularly lauryl alcohol (Orvis Extra), alkyl naphthalene sodium sulfonates (Alkanol B, the trade name of the Du Pont Company for propylated naphthalene sulfonate, and Alkanol DD), alkyl aryl sulfonates (Santomerse No. l, the trade name of the Monsanto Chemical Company for its mixture of 40% dodecyl benzene sodium sulfonate and 60% sodium sulfate), and dialkyl sodium sulfosuccinate, particularly the dioctyl compound (Aerosol OT). The magnesium compound employed introduces a degree of hardness into the cleaning solution, and it will be understood that where lower limits of magnesium compound are employed, a lesser amount of wetting agent will be required than where larger amounts of magnesium compound are used. It is desirable in most cases to also employ a compound active to prevent corrosion of the portion of the metal structure which is completely immersed in the cleaning solution. Tannic acid used in amounts of about .5 to 5% by weight performs this function very satisfactorily.

Benzaldehyde is added to the composition in amounts of about 1% to 3% by weight, and acts to control corrosion above the level of the cleaning solution, which may be trapped in contact with structural members. The action of the benzaldehyde in this respect is clearly demonstrated by a comparison of Examples 1 and 2, in the latter of which benzaldehyde was omitted from the formulation.

Example 1 A cleaning composition was formulated by dry mixing together the following compounds in the proportions, by weight, indicated:

sodium hexametaphosphate.)

An aqueous solution of this composition was prepared by adding it to water in the amount of 4 oz. of composiserved above the liquid level.

tion per gallon of water. The pH value of the resulting solution was about 1. The solution was employed in cleaning the exterior of a passenger car which was soiled by heavy encrustations of calcium carbonate and ferric oxide. The solution easily cut the encrustations and exhibited superior wetting and cleaning properties as the surfaces were easily rinsed and dried. A portion of the solution was purposely passed through the exterior paneling of the car to form a substantial pool between the inner and outer walls wherein the strength members of the car were located. The structural members were examined after having been in contact with the cleaning solution for about a month, and only a trace of corrosion was ob- The bi-phase level was free of a prohibitive amount of corrosion, as was the portion of the ,strength member which was completely immersed in the cleaning solution.

Example 2 A cleaning composition was formulated as described in Example 1 except that benzaldehyde was omitted and the content of sodium acid sulfate was increased a corresponding amount. The solution was tested under exactly the same circumstances as described in connection with Example 1 and it was found that a moderate amount of corrosion had occurred on the part of the structural member immediately above the liquid level. At the same time it was also observed that the cleaning solution formed according to Example 1 had better wetting and cleaning properties.

Example 3 A cleaning composition formulated by weight, as indicated below was tested as described in connection with Example 1 with equally satisfactory results:

Example 4 A cleaning composition formulated by weight, as indicated below, was tested as described in connection with Example 1 with equally satisfactory results:

Percent Calgon 1.00 CMC 2.00 MgSO, 5.00 Benzaldehyde 3.00 Santomerse No. 1 2.00 Aerosol OT 2.00 Glim 2.00 NaHSO; 83.00

Example 5 A cleaning composition formulated by weight, as indicated below, was tested as described in connection with Example 1 with equally satisfactory results:

Percent Calgon 5.00 CMC 3.00 Tannic acid 5.00 MgSO; 10.00 Benzaldehyde 2.00 Santomerse No. 1 5.00

Naaso, 70.00

Example 6 A cleaning composition formulated by weight, as indicated below, was tested as described in connection with Example 1 with equally satisfactory results:

Percent Calgon 1.00 CMC 1.00 Tannic acid 1.00 MgSO, 5.00 Benzaldehyde 1 .80 Glim 6.00 NaHSO, 84.20

Example 7 A cleaning composition formulated by weight, as indicated below, was tested as described in connection with Example 1 with equally satisfactory results:

What is claimed is:

1. The process of cleaning the surface of railroad rolling stock which comprises applying to said surface an aqueous solution containing for each gallon thereof about four ounces of a mixture consisting essentially, on a dry weight basis, of about 3-6% at least one synthetic wetting agent having surface activity at a pH of l and selected from non-ionic and anionic agents exclusive of soap, about .25 to 10% of a water-soluble magnesium compound selected from the group consisting of magnesium sulfate and magnesium chloride, a minor proportion up to about 3% of a water-soluble cellulose dispersing agent, a minor proportion up to about 5% of the molecularly dehydrated phosphate salt of an alkali metal, about 13% benzaldehyde, and the remainder sodium acid sulfate, the solution having a pH of about one.

2. A composition for use in the process of claim 1 consisting essentially, on a dry weight basis, of about 36% of at least one synthetic wetting agent having .surface activity at a pH of 1 and selected from non-ionic and anionic agents exclusive of soap, about .25 to 10% of a water-soluble magnesium compound selected from the group consisting of magnesium sulfate and magnesium chloride, a minor proportion up to about 3% of a watersoluble cellulose dispersing agent, a minor proportion up to about 5% of the molecularly dehydrated phosphate salt of an alkali metal, about 1-3% benzaldehyde, and the remainder sodium acid sulfate.

3. The process of claim 1 wherein said mixture includes about 1% tannic acid.

I 4. The process of claim 1 wherein said mixture includes at least about .10% of said dispersing agent and about .15 of said phosphate salt.

References Cited in the file of this patent UNITED STATES PATENTS 1,470,225 Holmes Oct. 9, 1923 2,418,955 Shawcross Apr. 5, 1947 2,525,178 Miller Oct. 10, 1950 2,593,259 Brissey Apr. 15, 1952 OTHER REFERENCES The Condensed Chem. Dictionary, 4th ed. (1950), page 123, Reinhold Publ. Co., N.Y. 

1. THE PROCESS OF CLEANING THE SURFACE OF RAILROAD ROLLING STOCK WHICH COMPRISES APPLYING TO SAID SURFACE AN AQUEOUS SOLUTION CONTAINING FOR EACH GALLON THEREOF ABOUT FOUR OUNCES OF MIXTURE CONSISTING ESSENTIALLY, ON A DRY WEIGHT BASIS, OF ABOUT 3-6% AT LEAST ONE SYNTHETIC WETTING AGENT HAVING SURFACE ACTIVITY AT A PH OF 1 AND SELECTED FROM NON-IONIC AND ANIONIC AGENTS EXCLUSIVE OF SOAP, ABOUT .25 TO 10% OF A WATER-SOLUBLE MAGNESIUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF MAGNESIUM SULFATE AND MAGNESIUM CHLORIDE, A MINOR PROPORTION UP TO ABOUT 3% OF A WATER-SOLUBLE CELLULOSE DISPERSING AGENT, A MINOR PROPORTION UP TO ABOUT 5% OF THE MOLECULARLY DEHYDRATED PHOSPHATE SALT OF AN ALKALI METAL, ABOUT 1-3% BENZALDEHYDE, AND THE REMAINDER SODIUM ACID SULFATE, THE SOLUTION HAVING A PH OF ABOUT ONE. 